Zygotene

Locusta migratoria

Lilium grandiflorum

Petunia hybrida

At zygotene (Gr. zygon = touching another), the stage after leptotene, the pairing of the homolog chromosomes (synapsis) begins. The homolog chromosomes are hold together by proteins (synaptomal complex). Next, crossing-over can happen between the DNA-double helices molecules of homolog chromosomes.